Why do cows huddle together?

Every year in summer certain questions reach us from all over the world: "Why do cows huddle together a specific moment of the day (around noon) in a certain area of the barn and won't move". This behaviour also stops at the same hour every day at the end of the afternoon. Is also disappears in the fall, when temperature drops.

We've checked out a lot of these cases and our conclusion is that it is caused by fresh air seeking behaviour. Cows stand as a group in the part of the barn where the air is fresh and avoid the areas where it isn't.

A behavioural component is the fact that in nature cows group together as a reaction to stinging and biting insects. We don't have the idea that insects are the main cause of huddling, but it is a given that insects won't be found in places with good air flow. So this instinct can strengthen huddling behaviour. Huddling also reduces the insect burden. It is a big difference when all flies in an area go for 1 cow, compared to when there are 10 cows.

Walk around your barn if you see huddling and use your nose to judge the air in different places. Our experience is that cows are always standing in places where the air is fresh and that the air in other places can be moist and warm, sometimes even outright unpleasant because of manure gasses.

In a significant number of cases that we had a look at, the behaviour started rather abruptly. These were all cases of a rebuild or of building an object that affected ventilation of the barn.

Insufficient ventilation causes more damage and problems than most dairy farmers know. Bad ventilation first of all makes that cows have to invest more energy into cooling themselves down, causing heat stress. It also creates higher infection pressure for bacteria's and viruses, leading to more hoof problems and udder infection. Furthermore lack of fresh air leads to higher concentrates of ammonia, which you can expect to be less than ideal for animals.

Farmers who want to improve their barn, should first have an expert (!) set up a ventilation plan for their entire barn. This is the foundation. This also includes a plan with arrangements to manage heat stress.

The independent experts of Vetvice can set up these plans for you: Nico Vreeburg (vreeburg@vetvice.nl / 06 51 83 43 96), Bertjan Westerlaan (westerlaan@vetvice.nl / 06 27 45 46 62) and Wiebe Veenstra (veenstra@vetvice.nl / 06 52 31 10 91).

We wish you and your cows all the best!

Jan Hulsen,
On behalf of CowSignals/Vetvice

Have you ever noticed this kind of huddling behaviour in summer, for example after a new construction changed the air flow? Can you share interventions that you made that were successful (no more huddling afterwards)? Please share below, together we know more!

(If you want to share pictures, please send them to Anouk to upload for you)

Comments (10)

Pran wali

Even undefined ways & mean of rearing , management of herd , & Above all the climatic changes during summer months. Rest of the parameters we prune to be ideal .

Pran Wali

In my prev commutes there was mismatch of my e-mail address. Sorry for intruption

Andrea Accola

Dass sich Kühe im Sommer trotz Hitze so zusammenstellen, hat mit der Fliegenplage zu tun. Sie stellen sich mit den Köpfen gegen das Zentrum in einem Kreis auf, um so der Fliegenplage entgegen zu wirken. Wenn nur zwei Tiere beieinander sind, so stellen sie sich häufig verkehrt zu einander auf. Mit dem Schwanz vertreiben sie sich so gegenseitig die Fliegen.

Gruss aus Graubünden
Andrea Accola

Dr.Bori Umar

This is one of natural habites of herbivorous animal for safety. Alway walking and standing in one group. In case of summer huddeling for cooling and in sunlight area to huddling to reduce surface area to sunlight. Also mostly closed yard sustem cow huddling at side from new fresh air coming and to see something new like vehicle, others animal crossing or other road side.

Carsten Houmann

Very good question. I have seen in Scandinavia - and I always find pure ventilation in those barns. Ventilation is importend. Right now I am in the States traveling. I have seen groups of beef cattle standing very close, and I was wondering why they stand so glose. I see two reasons: Naturally the cows will protect the calves born this year- they were standing in the middle of the group, - and next they were standing on a windy place- and the way the stand they also makes shadows fore the calves.

hassan khan

yes i experienced in my work place two years back in Government-run farm where are nearly 06 numbers of sheds......All are well ventilated but cows huddling occur in one shed whose direction is not according to the role. it has been taught us that the wind direction is always from north to south in this part of the world hence it is advised by the expert to keep the animal houses open / ventilated from N__S and closed the house on E___W. since the shed is closed on N____S and open on E__W hence there is no air circulation and dampness is prevailing in winter where temperature ranges from 0c to 10c. A serious out break of ring worms take place in winter and spread sporadically in the same shed. since we cannot change the direction now due to laws hence no animals are kept in winter in the same shed ,

Joep Driessen

Thanks for the great reactions everyone, great to read about different experiences. Keep them coming!


Hi. This may sound very curious, but I tried to enter berween cows who stays close together with each other in hot weather. I was quite surprised when I discovered that temperature in the midle is lower than I thought should be!! So, my conclusion is - this is very smart habit or action what cows use to cool down!
Best regards, Vita

Susanne Pejstrup

Recently I have seen it in an open barn with more fans and ventilators and scrapers in the alley. The cows were in some of the barns standing in the middle even the air was better at the ends. Could it be stray voltage / leakage current from the motors to the scraper system and the gates at the end?

Karl Burgi

In my opinion the three things to keep in mind when cows huddle is:
1. In hot weather cows associate light with being hot. Cows will lay out in the sun until their body temperature rises to a certain level (their threshold) than they will go for some shade or into a barn where it is dark. Many times they huddle in the darkest places of the barn with the poorest air quality.
2. I have seen it many times with barns facing east and west. In the morning during sun rise there will be no cows on the east end of the open barns and in the afternoon during sun set there will be no cows on the west end of the barn. If there is not even lighting throughout a barn and air velocity is not there cows will congregate in the darkest part or the middle of the barn. Similar things are happening with north and south barns. If there is freestalls on the outside wall and the sun hits them cows will not lay in them during hot weather unless they are shaded and have good air velocity.
3. Flies will make cows huddle together in larger groups also. This is made worse if there is pour windspeed especially in the resting areas.

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